﻿/*

The MIT License

Copyright (c) 2010 Cartesian Analytics, Inc. 

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

*/

using System;
using System.Collections.Generic;
using System.Linq;
using Pipra.Math;
using Pipra.Math.Geometry;

namespace Pipra.Gis.Projection
{
    /// <summary>
    /// Projection base class.
    /// </summary>
    public abstract class ProjectionBase :
        IProjection<LatLon, Point2>,
        ICoordinateOperationInfo
    {
        internal const double QuarterPi = System.Math.PI / 4.0;
        internal const double HalfPi = System.Math.PI / 2.0;

        protected readonly double MajorAxis;
        protected readonly double ESq;
        protected readonly double E;
        protected readonly double EHalf;
        /// <summary>
        /// The false projected offset.
        /// </summary>
        public readonly Vector2 FalseProjectedOffset;
        /// <summary>
        /// The spheroid.
        /// </summary>
        public readonly ISpheroid<double> Spheroid;

        protected ProjectionBase(
            ICoordinatePair<double> falseProjectedOffset,
            ISpheroid<double> spheroid
        )
        {
            if (null == spheroid)
            {
                throw new ArgumentNullException("spheroid");
            }
            Spheroid = spheroid;
            FalseProjectedOffset = new Vector2(falseProjectedOffset);
            MajorAxis = spheroid.A;
            ESq = spheroid.ESquared;
            E = spheroid.E;
            EHalf = E / 2.0;
        }

        public abstract Point2 TransformValue(LatLon source);

        public virtual IEnumerable<Point2> TransformValues(IEnumerable<LatLon> values)
        {
            return values.Select(TransformValue);
        }

        public abstract ITransformation<Point2, LatLon> GetInverse();

        public abstract bool HasInverse { get; }

        ITransformation ITransformation.GetInverse()
        {
            return GetInverse();
        }

        public virtual IEnumerable<INamedParameter> GetParameters()
        {
            return new INamedParameter[]
            {
                new NamedParameter<double>("false easting",FalseProjectedOffset.X), 
                new NamedParameter<double>("false northing", FalseProjectedOffset.Y),
                new NamedParameter<double>("semi major", Spheroid.A),
                new NamedParameter<double>("semi minor", Spheroid.B)
            };
        }

        public abstract string Name { get; }
    }
}
